Metal-Free Pyrene-Based Conjugated Microporous Polymer Catalyst Bearing N- and S-Sites for Photoelectrochemical Oxygen Evolution Reaction

• Published in: Frontiers in chemistry Vol. 9; p. 803860
• Main Authors: Das, Sabuj Kanti, Shyamal, Sanjib, Das, Manisha, Mondal, Saptarsi, Chowdhury, Avik, Chakraborty, Debabrata, Dey, Ramendra Sundar, Bhaumik, Asim
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 24.12.2021
• Subjects: Chemistry; conjugated microporous polymer; high surface area; metal-free heterogeneous photoelectrocatalyst; OER; water splitting; metal-free heterogeneous photoelectrocatalyst; water splitting; OER; conjugated microporous polymer; high surface area
• ISSN: 2296-2646; 2296-2646
• DOI: 10.3389/fchem.2021.803860

The development of an efficient, sustainable, and inexpensive metal-free catalyst for oxygen evolution reaction (OER) via photoelectrochemical water splitting is very demanding for energy conversion processes such as green fuel generators, fuel cells, and metal-air batteries. Herein, we have developed a metal-free pyrene-based nitrogen and sulfur containing conjugated microporous polymer having a high Brunauer-Emmett-Teller surface area (761 m 2  g −1 ) and a low bandgap of 2.09 eV for oxygen evolution reaction (OER) in alkaline solution. The π -conjugated as-synthesized porous organic material (PBTDZ) has been characterized by Fourier transform infrared spectroscopy (FT-IR), solid-state 13 C (cross-polarization magic angle spinning-nuclear magnetic resonance) CP-MAS NMR, N 2 adsorption/desorption analysis, field-emission scanning electron microscope (FESEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) experiments. The material acts as an efficient catalyst for photoelectrochemical OER with a current density of 80 mA/cm 2 at 0.8 V vs. Ag/AgCl and delivered 104 µmol of oxygen in a 2 h run. The presence of low bandgap energy, π -conjugated conducting polymeric skeleton bearing donor heteroatoms (N and S), and higher specific surface area associated with inherent microporosity are responsible for this admirable photoelectrocatalytic activity of PBTDZ catalyst.